title: Suppression of voltage-gated Na(+) channels and neuronal excitability by imperatorin.
abstract: Imperatorin is a naturally occurring furocoumarin compound isolated from plants such as Angelica archangelica and Cnidium monnieri. It has multiple pharmacological effects including anticonvulsant effects. Here we determined the effects of imperatorin on voltage-gated Na(+) channels (VGSC) using whole-cell patch clamp techniques in differentiated neuronal NG108-15 cells. We showed that imperatorin inhibited VGSC; such inhibition did not show state-dependence. Imperatorin caused a left shift in the steady-state inactivation curve without affecting activation gating. The inhibition of VGSC by imperatorin displayed a mild frequency-dependence. Imperatorin was also shown to inhibit VGSC and action potential amplitude without affecting voltage-gated K(+) channels in rat hippocampal CA1 neurons. In conclusion, our results suggest that imperatorin dampens neuronal excitability by inhibiting VGSC.
authors.affiliation: Department of Anesthesiology, Eda-Hospital, I-Shou University, Kaohsiung, Taiwan.
authors.forename: King-Chuen
authors.initials: KC
authors.lastname: Wu
authors.forename: Yi-Hung
authors.initials: YH
authors.lastname: Chen
authors.forename: Ka-Shun
authors.initials: KS
authors.lastname: Cheng
authors.forename: Yueh-Hsiung
authors.initials: YH
authors.lastname: Kuo
authors.forename: Chin-Tsang
authors.initials: CT
authors.lastname: Yang
authors.forename: Kar-Lok
authors.initials: KL
authors.lastname: Wong
authors.forename: Yuan-Kun
authors.initials: YK
authors.lastname: Tu
authors.forename: Paul
authors.initials: P
authors.lastname: Chan
authors.forename: Yuk-Man
authors.initials: YM
authors.lastname: Leung
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005260:Female; D011564:Furocoumarins / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000166:cytology* / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D061567:Voltage-Gated Sodium Channel Blockers / Q000494:pharmacology*; D061566:Voltage-Gated Sodium Channels / Q000378:metabolism*
chemical_list: D011564:Furocoumarins; D061567:Voltage-Gated Sodium Channel Blockers; D061566:Voltage-Gated Sodium Channels; C031534:imperatorin
keywords: Hippocampal CA1 neurons; Imperatorin; NG108-15 cells; Voltage-gated Na(+) channels